Split Coverage Concepts Vs. Spread Formations

May 29, 2011 | Defense, Coverage, Split Field Coverage Structures

By Mike Kuchar Senior Research Manager X&O Labs [email protected]

Researchers' Note: You can access the raw data - in the form of graphs - from our research of split coverage concepts: Click here to read the Statistical Analysis Report.

When teaching coverage to players, the install progression is becoming all too familiar with defensive coaches.  It’s the whole, part, whole theory.  First teach the entire coverage (whether by whiteboard or walk though), next break it down by position grouping and finally rep it on the field during seven-on-seven or team sessions.  Sure, it may simple but when offenses start to dictate personnel by changing formations, they’ve taken it to a whole other level.

No longer can defenses make a living staying in "country cover three" and one coverage against all formations.  Offenses are too sophisticated, and too well coached, for that. Most QB’s and coordinators will diagnose the voided areas within seconds (regardless of how well you disguise) and pepper your secondary with first downs.  It’s because of this that defenses have gone to more split coverage concepts – playing one half of the formation, or field, differently than the other.  Truth is, only 5.9% of the coaches we surveyed actually stay in the original coverage called.  The rest make their checks pre-snap based on personnel and formation.  So, while the offense may be dictating  coverage, most d-coordinators will argue they will have the last check and time to adjust by the time the ball is snapped.

Before we get into the most common coverage adjustments, it’s important to examine the "why" before the "how" as to playing split field coverage.  Based on our research, the coaches we spoke with check their coverage based on three potential variants:

  1. Unbalanced sets – 3x1 (trips) or 3x2 (empty)
  2. Personnel groupings, most usually based on tight end or no tight end personnel, for the threat of a consistent run game
  3. Field/Boundary tendencies

Based on our research, some of the more common split field coverage’s we found are:

  • Cover-four mixed with cover-two
  • Robber coverage mixed with cover-two
  • Robber coverage mixed with man
  • Man coverage mixed with quarters

The strong side of the defense can be predicated by field position (such as field or boundary) or by receiver strength – coaches call it both ways.  We’ve found that many of our coaches utilize their split field coverage concepts mainly against 3x1 or 3x2 formations.  Reason being is the myriad amounts of potential routes that offenses can sting you with. Quite simply, football is still a numbers game, and defenses need to account for offensive numbers. So if an offense comes out in an unbalanced offensive set (where there are more receivers on one side of the formation than the other) the defense needs to account for that.  Our researchers at X&O Labs found the most common checks defensive coordinators will make and how they teach their players to play them.


Case 1: Split Coverage Checks Dictated By Unbalanced (3x1) Formations Handling trips formations is always a cause for concern among defensive coaches.  In fact, 47.5% of coaches we surveyed are most concerned with the various route combinations from trips formations rather than aspects such as the skill of the back-side X receiver or the run ability of the QB or back.  Trips can be classified as any three eligible receivers to one side of the formation, which can or cannot include a tight end.  Over 41% of coaches that took part in our research use some sort of split field coverage to defend trips – mainly because it’s unbalanced by nature and offenses are stretching the field vertically with four possible immediate threats.

Assessing an opponent’s offensive personnel is imperative before devising a game plan and we all know that our adjustments can vary from week to week, but most coordinators have specific ways in which they will defend trips by nature.  Trips presents the immediate threat of four receivers going vertical at the snap of the ball into the four deep areas of the zone.  These same receivers can be employed to affect four potential horizontal areas in a zone.  Because of this, coordinators are no longer teaching spot drop zones in coverage.  Instead, they are teaching man principles to zone defenders by having them "lock" on once a defender enters their area of coverage.  This can be achieved through communication and recognition.

For example, Haskel Buff, the defensive coordinator at Fort Valley State University (D-II), defines anything vertical as clearing LB depth.  The Wildcats base their defenses out of the 4-2-5 scheme with a two-deep shell.  Buff plays with a four down front, two interior backers, three safeties and two corners.